Modified high-cis polybutadiene polymer, related methods and tire components

Abstract

Disclosed herein area process for preparing a modified high-cis polybutadiene polymer, a modified high-cis polybutadiene polymer, and tires having a component made using the modified high-cis polybutadiene polymer. The processes make use of a functionalizing compound of formula (I) to prepare the modified high-cis polybutadiene from a quantity of 1,3-butadiene monomer using a specified catalyst system.

What is claimed is: 
     
       1. A modified high-cis polybutadiene polymer having
 polymer chains bonded to a residue of a functionalizing compound having formula (I) as follows 
 
       
         
           
           
               
               
           
         
         where X is a cyano group,
 R 1  is independently selected from hydrocarbylene of C 1 -C 20  optionally containing one unsaturated carbon-carbon bond, 
 
         each R′ is independently selected from alkoxy of C 1 -C 20 , and 
         wherein each polymer chain is bonded to the residue of the functionalizing compound through the X group, and the polymer has 
         a cis 1,4-bond content of 92-98%, 
         an initial Mooney viscosity ML 1+4  at 100° C. of 20-100, and 
         an aged Mooney viscosity ML 1+4  at 100° C. of no more than 120, as determined after aging at 100° C. for 2 days. 
       
     
     
       2. The high-cis modified polybutadiene polymer of  claim 1 , wherein the cis 1,4-bond content is at least 94%. 
     
     
       3. The high-cis modified polybutadiene polymer of  claim 1 , meeting at least one of the following:
 a. has a Mw of 150,000 to 2,000,000 grams/mole; 
 b. has a Mn of 80,000 to 800,000 grams/mole; 
 C. has a Mw/Mn of 1.5 to 4; or 
 d. has an initial Mooney viscosity ML 1+4  at 100° C. of 40 to 70. 
 
     
     
       4. The high-cis modified polybutadiene polymer of  claim 3 , wherein each of (a)-(d) is met. 
     
     
       5. A process for preparing the modified high-cis polybutadiene polymer of  claim 1 , the process comprising
 A. providing a catalyst system comprising
 a. a lanthanide-based catalyst system comprising (i) a lanthanide compound, (ii) an alkylating agent, and (iii) a halogen source, where (iii) may optionally be provided by (i), (ii), or both (i) and (ii), 
 b. a nickel-based catalyst system comprising (i) a nickel compound, optionally in combination with an alcohol, (ii) an organoaluminum, organomagnesium, organozinc compound, or a combination thereof, and (iii) a fluorine-containing compound or a complex thereof, or 
 c. a cobalt-based catalyst system, comprising (i) a cobalt compound, (ii) an organo aluminum halide, and (iii) optionally water; 
 
 B. using the catalyst system of (A) to polymerize 1,3-butadiene to produce polymer chains with a living end, 
 C. reacting the living end polymer chains from (B) with a functionalizing compound having formula (I) as follows 
 
       
         
           
           
               
               
           
         
         
            where X is a cyano group, 
           R 1  is independently selected from hydrocarbylene of C 1 -C 20 , optionally containing one unsaturated carbon-carbon bond, 
           each R′ is independently selected from alkoxy of C 1 -C 20 , and 
           thereby producing a modified high-cis polybutadiene, 
         
         D. reacting the modified high-cis polybutadiene from (C) with
 (1) a stabilizing agent of formula (II) as follows
   R 2   n Si(OR 3 ) 4-n    
 
 wherein R 2  is selected from the group consisting of C 1  to C 20  alkyl, C 4  to C 10  cycloalkyl, or C 5  to C 20  aromatic groups, 
 wherein R 3  may be the same as or different from R 2  and is selected from C 1  to C 20  alkyl, C 4  to C 10  cycloalkyl, or C 5  to C 20  aromatic groups, and 
 n is an integer of 1 to 3, and 
 (2) a quenching agent of formula (III) as follows
   R 4 COOH 
 
 wherein R 4  is selected from H and the group consisting of C 1  to C 18  alkyl, and 
 
         E. isolating the modified high-cis polybutadiene of (D), to produce the modified high-cis polybutadiene of  claim 1 . 
       
     
     
       6. The process of  claim 5 , wherein the modified high-cis polybutadiene has a cis 1,4-bond content of at least 94%. 
     
     
       7. The process of  claim 5 , wherein the isolated modified high-cis polybutadiene has an initial Mooney viscosity ML 1+4  at 100° C. of 30-80. 
     
     
       8. The process of  claim 5 , wherein the isolated modified high-cis polybutadiene has an aged Mooney viscosity ML 1+4  at 100° C. of no more than 105. 
     
     
       9. The process of  claim 5 , wherein the functionalizing compound of formula (I) is used in a molar ratio of 100:1 to 0.5:1, the molar ratio based upon the moles of functionalizing compound: moles of primary metal of the catalyst system. 
     
     
       10. The process of  claim 5 , wherein the stabilizing agent of formula (II) is used in a molar ratio of 0.1:1 to 50:1, the molar ratio based upon the moles of stabilizing agent: moles of functionalizing compound. 
     
     
       11. The process of  claim 5 , wherein the quenching agent of formula (III) is used in a molar ratio of 0.1:1 to 10:1, the molar ratio based upon the moles of quenching agent: moles of stabilizing agent of formula (II). 
     
     
       12. The process of  claim 5 , wherein the stabilizing agent of formula (II) comprises octyltriethoxysilane. 
     
     
       13. The process of  claim 5 , wherein the quenching agent of formula (III) comprises 2-ethylhexanoic acid. 
     
     
       14. The process of  claim 5 , wherein the catalyst system is a lanthanide-based catalyst system (a). 
     
     
       15. The process of  claim 5 , wherein the modified high-cis polybutadiene meets at least one of the following:
 a. has a Mw of 150,000 to 2,000,000 grams/mole; 
 b. has a Mn of 80,000 to 800,000 grams/mole; 
 c. has a Mw/Mn of 1.5 to 4; or 
 d. has an initial Mooney viscosity ML 1+4  at 100° C. of 40 to 80. 
 
     
     
       16. The process of  claim 15 , wherein each of (a)-(d) is met.